Data from: The morphology of the inner ear of squamate reptiles and its bearing on the origin of snakes

The inner ear morphology of 80 snake and lizard species, representative of
a range of ecologies, is here analysed and compared to that of the fossil
stem snake Dinilysia patagonica, using three-dimensional geometric
morphometrics. Inner ear morphology is linked to phylogeny (we find here a
strong phylogenetic signal in the data that can complicate ecological
correlations), but also correlated with ecology, with Dinilysia resembling
certain semi-fossorial forms (Xenopeltis and Cylindrophis), consistent
with previous reports. We here also find striking resemblances between
Dinilysia and some semi-aquatic snakes, such as Myron (Caenophidia,
Homalopsidae). Therefore, the inner ear morphology of Dinilysia is
consistent with semi-aquatic as well as semi-fossorial habits: the most
similar forms are either semi-fossorial burrowers with a strong affinity
to water (Xenopeltis and Cylindrophis) or amphibious, intertidal forms
which shelter in burrows (Myron). Notably, Dinilysia does not cluster as
closely with snakes with exclusively terrestrial or obligate burrowing
habits (e.g. scolecophidians and uropeltids). Moreover, despite the above
similarities, Dinilysia also occupies a totally unique morphospace,
raising issues with linking it with any particular ecological category.